Both wired and wireless communications systems are migrating from a traditional circuit-switched architecture to a more flexible packet-switched architecture. With packet-switched communications, each communications session is decomposed into exchanges of a series of small data packets, each of which contains addressing information in its header to allow for flexible, independent routing of each data packet. The data packets are sent from the source to a destination via a cascade of transmission paths and network nodes. The transmission paths may differ for each packet depending on routing decisions made at each network node.
Wireless communications networks are also adopting a packet-switched communications mode. In one example, Universal Mobile Telecommunications System (UMTS) includes packet-oriented communications such as high-speed downlink packet access (HSDPA) and high-speed uplink packet access (HSUPA). In some cases, active data transmission occurs intermittently over a long time period. On the other hand, the system wants to avoid frequent connection termination and re-establishment to minimize data overhead and setup delay. Wireless providers aim to offer a perceived continuous connection similar to those offered by typical fixed broadband networks, for example, digital subscriber line (DSL) technology. However, maintenance of active control channels to keep a packet-switched communication mode available can result in an undesired increased noise level impacting system user capacity.
Continuous packet data connection (CPC) is an enhancement to Universal Mobile Telecommunications System (UMTS) to keep a high-speed packet channel in active state for a long time period without data transfer by reducing signaling during this time. Configuration of the CPC involves both semi-static and dynamic parameters settings. Since a global parameter (e.g., UE_DTX_DRX_Enabled) is used in the 3rd Generation Partnership Project (3GPP) standard, the discontinuous transmission (DTX) and discontinuous reception (DRX) configurations take place at the same time upon setting the global parameter. However, because of the uplink (UL) and downlink (DL) channel sub-frame offset, it is not feasible to achieve fine time alignment of the UL/DL channels for various continuous packet data connection (CPC) channels.